An atom of silicon needs to gain 4 electrons in its 3p sublevel to attain the noble gas electron configuration of argon, the noble gas in period 3 of the Periodic Table.
Silicon has 4 valence electrons. No noble gases will have 4 valence electrons.
The noble gas configuration of silicon is [Ne] 3s^2 3p^2, where [Ne] represents the electron configuration of the noble gas neon. Silicon has 14 electrons, with two in the 3s orbital and two in the 3p orbital.
The electron configurartion of silicon is [Ne]3s23p2.
The element with three occupied principal energy levels and four valence electrons is silicon (Si), which is in group 14 of the periodic table. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p². The noble gas configuration for silicon can be expressed as [Ne] 3s² 3p², where [Ne] represents the electron configuration of neon, the nearest noble gas preceding silicon.
Calcium loses two electrons to obtain a noble-gas electron configuration.
Silver (Ag) has 47 electrons. To achieve a pseudo-noble-gas electron configuration, silver would need to lose one electron to achieve a stable electron configuration that resembles a noble gas configuration like argon.
Two electrons
Selenium should gain two electrons and lose six electrons to achieve a noble gas electron configuration.
Calcium's electron configuration is [Ar] 4s2. To attain a noble gas configuration, calcium must lose 2 electrons to have the same electron configuration as argon, 4s2 3d10.
Aluminum has 13 electrons. To achieve a noble gas electron configuration like neon, aluminum needs to lose 3 electrons to have the same electron configuration as neon (10 electrons). This results in the formation of the Al3+ ion.
Chlorine gains 1 electron to achieve the noble gas electron configuration of argon.
Calcium (Ca) has 20 electrons in its neutral state. To attain a noble gas electron configuration (like argon), calcium would need to lose 2 electrons to have the same electron configuration as argon, as argon has 18 electrons.